This paper reviews results from the in-depth investigation of a series of fifteen, real-world, motorvehicle collisions. Primary criteria for this study were that the case vehicle should have been involved in an impact approximating a 50 km/h, frontal, barrier collision, and that at least one of the vehicle's occupants was fully-restrained. Particular attention is paid to the severity of the collisions and their relationship to full-scale barrier crash tests. In addition, the manner of use of individual restraint systems, and the mechanisms of occupant injury are discussed. The results of this study provide a valuable insight into the performance of three-point restraints in severe frontal collisions. This study forms part of a major research effort in Canada intended to develop improved criteria for the performance of occupant restraint systems. Part of this project involves producing new test devices and methodologies which, eventually, may be included in the Canadian motor vehicle safety regulations. Initially, the scope of the project has been restricted to a consideration of fully-restrained occupants in frontal impacts. The work has included modifications to the Hybrid III dummy to provide better bio-fidelity with respect to both seat belt loading of the thorax, and the potential for facial bone fractures. In order to evaluate the validity of these modifications, an in-depth investigation programme has been conducted on real-world collisions. The cases reported here form part of this investigative programme.